The invention relates to a modular electronic device. More specifically, the electronic device has a cabinet frame. The modules have module frames. Printed circuit boards are held in the module frames. Electronic components are mounted on the printed circuit boards. The modules with the module frames are pushed into the cabinet frame side-by-side and can be pulled out individually.
Furthermore the invention relates to a method of communication between such modules.
In avionics, different avionic functions are installed in autonomous units. When a failure occurs, the whole unit will be exchanged. Quite often, this unit consists of a housing in which the individual avionic functions are installed. The tendency, in avionics, is, however, using modular systems. This offers the advantage that, in the case of a failure of an avionic function, it will not be necessary to exchange the whole unit, but only the failing module needs to be exchanged. As a rule, these modules are printed circuit boards cannying electronic components. The printed circuit boards are mounted in a module frame, which can be pushed into a cabinet frame.
Information has to be exchanged between the individual modules. In the prior art, the communication is established through a data bus extending in the back wall of the cabinet frame. When the module are pushed into the cabinet frame, they are interconnected through appropriate plug-and-socket connectors connecting each module with the data bus.
The priciple of data busses is well known. A classical xe2x80x9cmulti-transmitter /multi-receiverxe2x80x9dxe2x80x94data bus is a multi-wire line for data transfer between a plurality of functional units. With such a bus structure, basically one transmission line is required, all units being connected with this transmission line. The communication of all units is carried out through through this transmission line. This is, on one hand, a simple structure. However this simple structure, on the other hand, requires a complex administration. As, in principle, all connected units are able to transmit and to receive messages, care has to be taken to prevent a plurality of different units from transmitting data simultaneously, and to ensure that only those units for which the instantaneously transmitted data are intended are switched on reception. Therefore, the administration of the bus is usually handled by a particular bus controller.
The ARINC-standard xe2x80x9cARINC 659xe2x80x9d describes a so-called xe2x80x9cbackplane busxe2x80x9d. The backplane bus is a bus system which is arranged in the back wall or backplane of a push-in cabinet. In this standard. The bus system is a so-called xe2x80x9cmultiplex-busxe2x80x9d German patent 41 32 994 describes a modular push-in system comprising modules with printed circuit boards, which carry electric components.
Published European patent application EP 0,824,302 A1 describes a modular electronic device with printed circuit boards carrying electric components. The printed circuit boards are mounted in module frames of push-in modules. The push-in modules, in turn, are retractably retained in a cabinet frame. The push-in modules are electrically connected with a backplane component.
Published German patent application 34 17 451 describes a right-parallelepipedal push-in system for an electronic device into which printed circuit board inserts or the like can be pushed in.
The prior art module communication of push-in insert cabinets suffers from the disadvantage that the safety of the data transfer from one module to another cannot be ensured without limitations. Avoiding collisions requires expensive organisation of the data flux. At the same time, however, this increases the error proneness of the data flux, as the communication processes between the individual modules are not mutually independent.
It has been found disadvantageous with prior art devices that conventional bus structures do not permit easy recognition, when the communication of a module is no longer operative.
It is an object of the invention to provide a modular electronic device which avoids the disadvantages of the prior art.
It is a further object of the invention to ensure that communication within the electronic device is collision-free, determined in time and, during data transmission, independent of other devices or internal functions.
To this end a modular electronic device comprising a cabinet frame, a plurality of push-in modules with module frames retained in said cabinet frame side-by-side, and printed circuit boards mounted in said module frames, and electronic components carried by said printed circuit boards is provided, wherein each of said modules has autonomous data transmitting means for communicating directly with each of the other ones of said modules.
In a method of communication between modules of a modular electronic device comprising a cabinet frame, a plurality of push-in modules with module frames retained in said cabinet frame, and printed circuit boards mounted in said module frames, and electronic components carried by said printed circuit boards, said modules are directly interconnected for data exchange.
Thanks to the direct transmission of the data from one module to another, freedom of collision during data transfer is achieved. The control of the communication between the modules is independent of the processor units of the modules. When direct communication of the modules with each other is used, it is considerably more easy than with the prior art to add further modules to a already communicating module system. The communication of already communicating modules is not disturbed by added modules.
Preferably, said data transmitting means of each of said modules comprise a data transmitting controller. This controller controls the data transmission to the other modules. Data memories provided in the respective modules and connected with the data transmitting means permits temporary storage of data.
A further advantageous modification is that the data transmitting means have both a transmitting device for data transmission and a corresponding receiver device. It may, however, also be sufficient if either a receiver device only is provided in the data transmission means or a transmitting device.
By using a time-controlled communication protocol, the data transmission becomes transparent and safer.
Interfaces at the modules establish, in the cabinet frame, the communication with the remaining modules.
Preferably, the electronic devices of the invention are used in aircraft. Then, the cabinet frame of the electronic device may be an integral part of the aircraft.